perf bench futex: Use cpumaps

It was reported that the whole futex bench breaks when dealing with
non-contiguously numbered cpus.

$ echo 0 | sudo tee /sys/devices/system/cpu/cpu3/online
$ ./perf bench futex all
 perf: pthread_create: Operation not permitted
 Run summary [PID 14934]: 7 threads, each ....

James had implemented an approach with cpumaps that use an in house
flavor. Instead of re-inventing the wheel, I've redone the patch such
that we use the perf's util/cpumap.c interface instead.

Applies to all futex benchmarks.

Suggested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Originally-from: James Yang <james.yang@arm.com>
Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: Kim Phillips <kim.phillips@arm.com>
Link: http://lkml.kernel.org/r/20171127042101.3659-2-dave@stgolabs.net
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 12 insertions, 7 deletions

diff --git a/tools/perf/bench/futex-hash.c b/tools/perf/bench/futex-hash.c
index 58ae6ed8f38b..2defb6df7fd0 100644
--- a/tools/perf/bench/futex-hash.c
+++ b/tools/perf/bench/futex-hash.c
@@ -24,6 +24,7 @@
 #include <subcmd/parse-options.h>
 #include "bench.h"
 #include "futex.h"
+#include "cpumap.h"
 
 #include <err.h>
 #include <sys/time.h>
@@ -118,11 +119,12 @@ static void print_summary(void)
 int bench_futex_hash(int argc, const char **argv)
 {
 	int ret = 0;
-	cpu_set_t cpu;
+	cpu_set_t cpuset;
 	struct sigaction act;
-	unsigned int i, ncpus;
+	unsigned int i;
 	pthread_attr_t thread_attr;
 	struct worker *worker = NULL;
+	struct cpu_map *cpu;
 
 	argc = parse_options(argc, argv, options, bench_futex_hash_usage, 0);
 	if (argc) {
@@ -130,14 +132,16 @@ int bench_futex_hash(int argc, const char **argv)
 		exit(EXIT_FAILURE);
 	}
 
-	ncpus = sysconf(_SC_NPROCESSORS_ONLN);
+	cpu = cpu_map__new(NULL);
+	if (!cpu)
+		goto errmem;
 
 	sigfillset(&act.sa_mask);
 	act.sa_sigaction = toggle_done;
 	sigaction(SIGINT, &act, NULL);
 
 	if (!nthreads) /* default to the number of CPUs */
-		nthreads = ncpus;
+		nthreads = cpu->nr;
 
 	worker = calloc(nthreads, sizeof(*worker));
 	if (!worker)
@@ -163,10 +167,10 @@ int bench_futex_hash(int argc, const char **argv)
 		if (!worker[i].futex)
 			goto errmem;
 
-		CPU_ZERO(&cpu);
-		CPU_SET(i % ncpus, &cpu);
+		CPU_ZERO(&cpuset);
+		CPU_SET(cpu->map[i % cpu->nr], &cpuset);
 
-		ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpu);
+		ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cpu_set_t), &cpuset);
 		if (ret)
 			err(EXIT_FAILURE, "pthread_attr_setaffinity_np");
 
@@ -217,6 +221,7 @@ int bench_futex_hash(int argc, const char **argv)
 	print_summary();
 
 	free(worker);
+	free(cpu);
 	return ret;
 errmem:
 	err(EXIT_FAILURE, "calloc");